Computing features of structured data

ABSTRACT

The present invention extends to methods, systems, and computer program products for computing features of structured data. Aspects of the invention include computing features of table components (e.g., of rows, columns, cells, etc.). Computed features can be used for ranking the table components. When aggregated, features for different components of a table can be used for ranking the table (e.g., a web table).

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

BACKGROUND

Background and Relevant Art

Computer systems and related technology affect many aspects of society.Indeed, the computer system's ability to process information hastransformed the way we live and work. Computer systems now commonlyperform a host of tasks (e.g., word processing, scheduling, accounting,etc.) that prior to the advent of the computer system were performedmanually. More recently, computer systems have been coupled to oneanother and to other electronic devices to form both wired and wirelesscomputer networks over which the computer systems and other electronicdevices can transfer electronic data. Accordingly, the performance ofmany computing tasks is distributed across a number of differentcomputer systems and/or a number of different computing environments.

Search engines can be used on networks, including the Internet, tolocate information of interest to a user. A search engine typically usesa crawler that continual crawls Web pages on a network, such as, theInternet, to index content. To find content, a user submits one or moresearch terms to the search engine. The search engine identifies pagesdeemed to contain content relevant to the one or more search terms. Thesearch engine then returns links to the identified pages back to theuser. The user can then select (e.g., “click”) a link to view content ofa corresponding page.

A structured data search system (SDSS) similarly crawls a network, suchas the Internet, to index structured information. Structured informationcan include tables in a relational database or HTML tables extractedfrom Web pages. To find structured data, a user submits one or moresearch terms to the SDSS. The SDSS identifies structured data, such as,a table, deemed to contain content relevant to the one or more searchterms. The search engine then returns the structured data back to theuser. The user can then integrate the structured data into theirapplications.

Due to the diversity of content generation on the Internet, thedefinition and content of structured data as well as the integration ofstructured data into a Web page can vary widely between different Webpages. As such, it can be difficult to effectively index structureddata, such as, tables. When structured data is not appropriatelyindexed, search results are less relevant.

Further, even when multiple portions of structured data (e.g., multipletables) are match search terms, there may be no way to determine anorder in which to present the different portions. Determining an orderbecomes increasingly difficult as the number of identified portionsincreases. For example, hundreds or even thousands of tables can bereturned as a match for entered search terms. Although some tables maybe more relevant than other tables, it may be difficult to identify morerelevant tables and present the more relevant tables prior to lessrelevant tables.

BRIEF SUMMARY

The present invention extends to methods, systems, and computer programproducts for computing features of structured data. Aspects of theinvention include computing features of table components (e.g., of rows,columns, cells, etc.). Computed features can be used for ranking thetable components. When aggregated, features for different components ofa table can be used for ranking the table (e.g., a web table).

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by the practice of the invention. Thefeatures and advantages of the invention may be realized and obtained bymeans of the instruments and combinations particularly pointed out inthe appended claims. These and other features of the present inventionwill become more fully apparent from the following description andappended claims, or may be learned by the practice of the invention asset forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and otheradvantages and features of the invention can be obtained, a moreparticular description of the invention briefly described above will berendered by reference to specific embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered to be limiting of its scope, the invention will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings in which:

FIG. 1 illustrates an example computer architecture that facilitatesbuilding one or more indexes from one or more datasets of structureddata.

FIG. 2 illustrates an example computer architecture that facilitatescomputing features of table entities.

FIG. 3 illustrates a flow chart of an example method for computingfeatures of table entities.

FIG. 4 illustrates an example computer architecture that facilitatescomputing features of table attributes.

FIG. 5 illustrates a flow chart of an example method for computingfeatures of table attributes.

FIG. 6 illustrates an example of computing features of table entities.

FIGS. 7A and 7B illustrate an example of computing features of tableattributes.

DETAILED DESCRIPTION

The present invention extends to methods, systems, and computer programproducts for computing features of tables. Aspects of the inventioninclude computing features of table components (e.g., of rows, columns,cells, etc.). Computed features can be used for ranking the tablecomponents. When aggregated, features for different components of atable can be used for ranking the table (e.g., a web table).

Embodiments of the present invention may comprise or utilize a specialpurpose or general-purpose computer including computer hardware, suchas, for example, one or more processors and system memory, as discussedin greater detail below. Embodiments within the scope of the presentinvention also include physical and other computer-readable media forcarrying or storing computer-executable instructions and/or datastructures. Such computer-readable media can be any available media thatcan be accessed by a general purpose or special purpose computer system.Computer-readable media that store computer-executable instructions arecomputer storage media (devices). Computer-readable media that carrycomputer-executable instructions are transmission media. Thus, by way ofexample, and not limitation, embodiments of the invention can compriseat least two distinctly different kinds of computer-readable media:computer storage media (devices) and transmission media.

Computer storage media (devices) includes RAM, ROM, EEPROM, CD-ROM,solid state drives (“SSDs”) (e.g., based on RAM), Flash memory,phase-change memory (“PCM”), other types of memory, other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium which can be used to store desired program code means inthe form of computer-executable instructions or data structures andwhich can be accessed by a general purpose or special purpose computer.

A “network” is defined as one or more data links that enable thetransport of electronic data between computer systems and/or modulesand/or other electronic devices. When information is transferred orprovided over a network or another communications connection (eitherhardwired, wireless, or a combination of hardwired or wireless) to acomputer, the computer properly views the connection as a transmissionmedium. Transmissions media can include a network and/or data linkswhich can be used to carry desired program code means in the form ofcomputer-executable instructions or data structures and which can beaccessed by a general purpose or special purpose computer. Combinationsof the above should also be included within the scope ofcomputer-readable media.

Further, upon reaching various computer system components, program codemeans in the form of computer-executable instructions or data structurescan be transferred automatically from transmission media to computerstorage media (devices) (or vice versa). For example,computer-executable instructions or data structures received over anetwork or data link can be buffered in RAM within a network interfacemodule (e.g., a “NIC”), and then eventually transferred to computersystem RAM and/or to less volatile computer storage media (devices) at acomputer system. Thus, it should be understood that computer storagemedia (devices) can be included in computer system components that also(or even primarily) utilize transmission media.

Computer-executable instructions comprise, for example, instructions anddata which, when executed at a processor, cause a general purposecomputer, special purpose computer, or special purpose processing deviceto perform a certain function or group of functions. The computerexecutable instructions may be, for example, binaries, intermediateformat instructions such as assembly language, or even source code.Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the described features or acts described above.Rather, the described features and acts are disclosed as example formsof implementing the claims.

Those skilled in the art will appreciate that the invention may bepracticed in network computing environments with many types of computersystem configurations, including, personal computers, desktop computers,laptop computers, message processors, hand-held devices, multi-processorsystems, microprocessor-based or programmable consumer electronics,network PCs, minicomputers, mainframe computers, mobile telephones,PDAs, tablets, pagers, routers, switches, and the like. The inventionmay also be practiced in distributed system environments where local andremote computer systems, which are linked (either by hardwired datalinks, wireless data links, or by a combination of hardwired andwireless data links) through a network, both perform tasks. In adistributed system environment, program modules may be located in bothlocal and remote memory storage devices.

Embodiments of the invention can also be implemented in cloud computingenvironments. In this description and the following claims, “cloudcomputing” is defined as a model for enabling on-demand network accessto a shared pool of configurable computing resources. For example, cloudcomputing can be employed in the marketplace to offer ubiquitous andconvenient on-demand access to the shared pool of configurable computingresources. The shared pool of configurable computing resources can berapidly provisioned via virtualization and released with low managementeffort or service provider interaction, and then scaled accordingly.

A cloud computing model can be composed of various characteristics suchas, for example, on-demand self-service, broad network access, resourcepooling, rapid elasticity, measured service, and so forth. A cloudcomputing model can also expose various service models, such as, forexample, Software as a Service (“SaaS”), Platform as a Service (“PaaS”),and Infrastructure as a Service (“IaaS”). A cloud computing model canalso be deployed using different deployment models such as privatecloud, community cloud, public cloud, hybrid cloud, and so forth. Inthis description and in the claims, a “cloud computing environment” isan environment in which cloud computing is employed.

In these description and the following claims, a “table” is defined asset of data elements (values) arranged in a two dimensional structureand having data along two axes. A table can include vertical columns andhorizontal rows. Columns and rows can be viewed interchangeably. When atable is rotated 90 degrees, columns can transition to rows and rows cantransition columns.

Each intersection of a row and column represents a cell. Rows can beidentified by the values appearing in a specified column subset, forexample, identified as a key index. Tables can be found in databases, inweb pages, in curated datasets, captured from images (e.g.,whiteboards), found in other files (e.g., Portable Document Format(“PDF”) files), or found in other sources, etc. Aspects of the inventioncan be used to understand tables from any of these sources.

One or more columns of a table can be subject columns. A subject columncontains the names of entities the table is about. Other columns in atable represent relationships or attributes of entities in a subjectcolumn. A subject column can be viewed as an approximate key.

A row of a table can be a column header. A column header for a tablecontains names of the table's columns.

Aspects of the invention include computing features of tables that canbe used for table ranking. For example, features of web tables can becomputed. The computed features can be used to rank web tables relativeto one another.

Index Build Architecture

FIG. 1 illustrates an example computer architecture 100 that facilitatesbuilding one or more indexes from one or more datasets of structureddata. Referring to FIG. 1, computer architecture 100 includes tableextraction and classification module 101, table understanding module102, table annotation module 103, feature computation module 104, indexbuilding module 106, web snapshot 111, curated dataset 112, click logs113, knowledge bases 114, and indexes 121, 122, and 123. Each of tableextraction and classification module 101, table understanding module102, table annotation module 103, feature computation module 104, indexbuilding module 106, web snapshot 111, curated dataset 112, click logs113, and knowledge bases 114, and indexes 121, 122, and 123 can beconnected to one another over (or be part of) a network, such as, forexample, a Local Area Network (“LAN”), a Wide Area Network (“WAN”), andeven the Internet. Accordingly, each of table extraction andclassification module 101, table understanding module 102, tableannotation module 103, feature computation module 104, index buildingmodule 106, web snapshot 111, curated dataset 112, click logs 113, andknowledge bases 114, and indexes 121, 122, and 123, as well as any otherconnected computer systems and their components, can create messagerelated data and exchange message related data (e.g., Internet Protocol(“IP”) datagrams and other higher layer protocols that utilize IPdatagrams, such as, Transmission Control Protocol (“TCP”), HypertextTransfer Protocol (“HTTP”), Simple Mail Transfer Protocol (“SMTP”), etc.or using other non-datagram protocols) over the network.

In general, computer architecture 100 can leverage web snapshot 111, andpossibly also one or more curated datasets 112, to build one or more ofindexes 121, 122, and 123. Computer architecture 100 can extract tablesfrom web snapshot 111 and/or one or more curated datasets 112,understand and annotate the extracted tables, and build one or more ofindexes 121, 122, and 123 based on the understanding/annotation of thetables. Indexes 121, 122, and 123 can then be used by an index servecomponent to retrieve candidate results to user queries as well as rankcandidate result tables based on relevance. Each of indexes 121, 122,and 123 can be a different type of index, such as, for example, a stringmapping index that maps tokens to identifiers and contains inversedocument frequencies of the tokens, a keyword (inverted) or featureindex that can be used to retrieve top ranked tables for user queries,or a table content index that can be used to generate previews/snippetsfor retrieved tables as well as fetch complete tables when requested.

Within computer architecture 100, table extraction and classificationmodule 101 can receive web snapshot 111 and/or curated data set 112 asinput. Web snapshot 111 can include tables in HyperText Markup Language(HTML) format. Curated dataset 112 can include tables in a site specificformat, such as, for example, data from data.gov or the World Bank. Websnapshot 111 and curated dataset 112 can be created using wrappersand/or crawlers that scrape sites, understand the format of those sites,and extract tables. For example, Web snapshot 111 can be created fromscraping the Internet. Thus, Web snapshot 111 can include web tables.The web tables can be relational or non-relational. Some tables mayexpressly define a subject column and column headers. Other tables maylack an express definition of a subject column and/or column headers.

Table extraction and classification module 101 can extract tables fromweb snapshot 111 and/or curated data set 112. Table extraction andclassification module 101 can filter out tables of no value, such as,for example, tables used for navigational/layout purposes. From anyremaining tables, table extraction and classification module 101 canclassify tables as relational and/or non-relational tables. In oneaspect, table extraction and classification module 101 also filters outnon-relational tables. Table extraction and classification module 101can output tables (e.g., relational tables) for use by other modules incomputer architecture 100.

Click logs 113 can include link selection information (“clicks”) loggedfor a plurality of network users. For the Internet, click logs 113 caninclude link selection information for a larger plurality of users.Knowledgebases 114 can include different classes of knowledgebase. Oneclass of knowledgebase can contain structured information about entitiesand/or relationships between entities, such as, for example, tables inweb snapshot 111 and/or curated dataset 112. For example, a knowledgebase can include information about table entities, including: entitynames, entity types, entity attributes, and values for entityattributes. Another class of knowledgebase are those extracted from Webdocuments (e.g., using text patterns).

Table understanding module 102 can receive tables (e.g., relationaltables) extracted by table extraction and classification module 101 asinput. Table understanding module 102 can use various different tableunderstanding algorithms to understand tables. Some tables may lackexpressly defined subject columns and/or expressly defined columnheaders. As such, table understanding algorithms can be configured toidentify subject columns for tables and/or detect column headers fortables when tables do not expressly define such information. Tableunderstanding module 102 can utilize click logs 113 and knowledgebases114 to assist with understanding tables. Table understanding module 102can output identified subject columns and detected column headers fortables.

Table annotation module 103 can receive tables (e.g., relational tables)extracted by table extraction and classification module 101. Tableannotation module 103 can also receive identified subject columns anddetected column headers for tables (e.g., from table understandingmodule 102). Table annotation module 103 can use various different tableannotation algorithms to annotate tables with relevant content that isnot expressly defined as being associated with tables. For example, on aweb page containing a table, content within <table> and </table> tags(e.g., cell values and column names) can be useful in supporting keywordand data finding searches.

However, there can also be additional content useful in supportingkeyword and data finding searches that is not within <table> and</table> tags. For example, additional content can be on a web pageoutside <table> and </table> tags, additional content can be in otherweb pages containing links to the web page, additional content can be inclick log data, etc. As such, table annotation algorithms can beconfigured to identify this additional content and annotatecorresponding tables with the additional content. Subsequently, indexbuilding module 106 can generate inverted index over this additionalcontent as well as content within <table> and </table> tags.

Table annotation module 103 can utilize click logs 113 and knowledgebases 114 to assist with identifying additional content and annotatingcorresponding tables with the additional content. Table annotationmodule 103 can output tables annotated with corresponding additionalcontent.

Feature computation module 104 can receive tables. Feature computationmodule 104 can use various feature computation algorithms to compute(static) features of tables. The computed (static) features can be usedfor ranking. For example, feature computation module 104 can computestatic (i.e., query independent) features of web tables for use inrelevant ranking. Rankings can be used to help surface better (e.g.,more reputed, more popular, or more relevant) web tables when many webtables satisfy a search query. Feature computation module 104 can outputcomputed (static) features for tables.

Feature computation module 104 can be used with annotated or unannotatedtables. When feature computation module 104 receives annotated tables,the various feature computation algorithms can use additional contentcontained in annotations to compute (static) features.

Index building module 106 can receive tables. Index building module 106can use various index building algorithms to build one or more ofindexes 121, 122, and 123 from received tables. Index building module106 can receive annotated or unannotated tables. When index buildingmodule 106 receives annotated tables, the various index buildingalgorithms can use additional content contained in annotations whenbuilding indexes. Index building module 106 can also access computed(static) features for tables. When index building module 106 accessescomputed (static) features for tables, the various index buildingalgorithms can use the computed (static) features when building indexes.

Computing Features of Table Entities

FIG. 2 illustrates an example computer architecture 200 that facilitatescomputing features of table entities. Referring to FIG. 2, computerarchitecture 200 includes occurrence rate calculation module 201,feature determination module 204, and query log 206. Each of occurrencerate calculation module 201, feature determination module 204, and querylog 206 can be connected to one another over (or be part of) a network,such as, for example, a Local Area Network (“LAN”), a Wide Area Network(“WAN”), and even the Internet. Accordingly, each of occurrence ratecalculation module 201, feature determination module 204, and query log206 as well as any other connected computer systems and theircomponents, can create message related data and exchange message relateddata (e.g., Internet Protocol (“IP”) datagrams and other higher layerprotocols that utilize IP datagrams, such as, Transmission ControlProtocol (“TCP”), Hypertext Transfer Protocol (“HTTP”), Simple MailTransfer Protocol (“SMTP”), etc. or using other non-datagram protocols)over the network.

Occurrence rate calculation module 201 and feature determination module204 can be included in feature computation module 104. Alternatively,occurrence rate calculation module 201 and feature determination module204 can operate outside of feature computation module 104.

Generally, occurrence rate calculation module 201 is configured todetermine the occurrence rate of table entities within other tablerelated data. As depicted, occurrence rate calculation module 201further includes table count module 202 and query count module 203.Table count module 202 is configured to count how many tables (e.g.,included in web snapshot 111) include a specified entity in theirsubject column. In some aspects, the specified entity is a value fromthe subject column of another table.

Query log 206 contains a log of issued search queries and correspondingclick counts for Uniform Resource Locations (URLs) selected from searchresults presented in response to the issued search queries. Query countmodule 203 is configured to access a URL click count for an entity fromquery log 206.

In one aspect, one of table count module 202 or query count module 203is used to calculate a count representing the popularity and/ortrustworthiness of an entity. In another aspect, table count module 202and query count module 203 interoperate to calculate a countrepresenting the popularity and/or trustworthiness of an entity.Popularity can indicate the frequency with which an entity is includedin other tables and/or is selected from search results (i.e., quantity).Trustworthiness can indicate how relevant an entity is based oninclusion in other tables and/or selection from search results (i.e.,quality).

Feature determination module 204 is configured to determine thepopularity and/or trustworthiness of a table by aggregating thedetermined popularity and/or trustworthiness of entities in the table.An aggregation function can be used to aggregate entity counts into afeature of the table. The aggregation function can determine featuresusing one or more of mean or median and various quantiles.

The aggregation function can be robust to ambiguities. For example, whenconsidering entity occurrences in other tables, the aggregation functioncan account for name ambiguities, such as, between a scientist namedMichael Jordan and the basketball player name Michael Jordan. Theaggregation function does not incorrectly increase the popularity of thescientist Michael Jordan is based on the popularity of the basketballplayer Michael Jordan. Ambiguity (e.g., name ambiguity) is lessproblematic when considering click counts because users can disambiguatethemselves prior to selecting a URL.

In one aspect, a knowledge base internally uses globally uniqueidentifiers (GUID's) for each entity. Table entities can be linked tothe knowledge base. Aggregation can then be performed for GUIDs.

FIG. 3 illustrates a flow chart of an example method 300 for computingfeatures of table entities. Method 300 will be described with respect tothe components and data of computer architecture 300.

Occurrence rate calculation module 201 can have access to a plurality oftables (e.g., web tables) including tables 211, 221, and 231. Theplurality of tables can be contained in web snapshot 111, curateddataset 112, etc. Occurrence rate calculation module 201 can access oneor more of the plurality of tables. Occurrence rate calculation module201 can interoperate with feature determination module 204 to determinetable features for accessed tables.

Method 300 includes accessing a table from among the plurality of tables(301). For example, occurrence rate calculation module can access table211. As depicted, table 211 is contained in web page 216. Web page 216is accessible via Uniform Resource Locator (URL) 217. Table 211 hassubject column 212, column 213, etc. Subject column 212 containsentities of the table including entities 212A, 212B, 212C, etc. Column213 contains corresponding attributes of the entities in (i.e., on thesame row as) subject column 212 including attributes 213A, 213B, 213C,etc. Other columns of table 211 contain other corresponding attributesof the entities in (i.e., on the same row as) subject column 212.

Similarly, table 221 has subject column 222, column 223, etc. Subjectcolumn 212 contains entities of the table including entities 222A, 222B,etc. Column 223 contains corresponding attributes of the entities in(i.e., on the same row as) subject column 222 including attributes 223A,223B, etc. Other columns of table 221 contain other correspondingattributes of the entities in subject column 222.

Likewise, table 231 has subject column 232, column 233, etc. Subjectcolumn 232 contains entities of the table including entities 232A, 232B,etc. Column 233 contains corresponding attributes of the entities in(i.e., on the same row as) subject column 232 including attributes 233A,233B, etc. Other columns of table 231 contain other correspondingattributes of the entities in subject column 232.

Other tables in the plurality of tables, such as, for example, tablesincluded in web snapshot 111, curated dataset 112, etc. can be similarlyconfigured.

Method 300 includes for each value in the subject column of the table,calculating an occurrence rate for the value by counting the occurrencesof the value within other table related data (302). For example,occurrence rate calculation module 201 can calculate an occurrence ratefor each of entities 212A, 212B, 213C, etc. by counting the occurrencesof each of entities 212A, 212B, 213C, etc. within other table relateddata. Calculating occurrences in other table related data can includecounting occurrences in other tables (table 221, table 231, other tablesin web snapshot 111, other tables in curated data set 112, etc.) and/oraccessing click count data from query log 206 (or click logs 113).

For example, for each of entity 212A, 212B, 2121C, etc., table countmodule 202 can calculate the number of occurrences of the entity in thesubject column of other tables. Table count module 202 can calculate howmany other tables include entity 212A in the subject column, how manyother tables include entity 212B in the subject column, how many othertables include entity 212C in the subject column, etc. For example,table count module 202 can determine if entity 212A is included insubject column 222, is included in subject column 232, etc.

Determining if an entity in the subject column of one table is includedin the subject column of another table can include comparing entities.For example, table count module 202 can compare entity 212A to entities221A, 222B, etc. to determine of entity 212A is included in table 221.Similarly, table count module 202 can compare entity 212A to entities231A, 232B, etc. to determine of entity 212A is included in table 231.Table count module 202 can also compare entity 212A to entities in thesubject column of other tables (e.g., included in web snapshot 111,curated dataset 112, etc.). Table count module 202 can perform similarcomparisons for entity 212B, 212C, etc.

A comparison algorithm can be robustly configured to account for less(or non) relevant differences between entities. For example, acomparison algorithm can account for different formats, minordifferences (misspellings, smaller differences in larger numbers, etc.)between entities, etc. or combinations thereof. For example, “Jordan,Michael” can be counted as “Michael Jordan” or vice versa. “MichealJordan” can also be counted as “Michael Jordan”. “1,560,437” can becounted as “1,560,386”. “1 million” can be counted as “1,000,231”.

Query count module 203 can refer to query log 206 (and/or click logs113) to access click count data for each entity, such as, entity 212A,entity 212B, entity 212C, etc., in a subject column. For example, querycount module 203 can submit entity 212A to query log 206. Query log 206can refer to log entry 248. Log entry 248 is for query 241 (a log entryfor a query that includes entity 212A). Log entry 248 indicates thatURLs 242, 217, and 243 have been selected from search results presentedin response to query 241. URLs 242, 217, and 243 are associated withcorresponding click counts 244, 246, and 247 respectively. Each clickcount indicates how often a corresponding URL was selected frompresented search results.

As described, URL 217 is the URL for accessing Web page 216. As such,query log 206 can return click count 246 to query count module 203 forentity 212A. Click count 246 indicates how often URL 217 was selectedfrom search results presented in response to query 241 (a query thatcontains entity 212A).

Query count module 203 can similarly refer to query log 206 (or clicklogs 113) for entity 212B, entity 212C, etc. to obtain correspondingclick counts.

In some aspects, table count module 202 calculates an occurrence ratefor an entity based on the number of occurrences of the entity in othertables. In another aspect, query count module 203 calculates anoccurrence rate for an entity based on a click count for the entity. Ina further aspect, table count module 202 and query count module 203interoperate to calculate an occurrence rate for an entity based on thenumber of occurrences of the entity in other tables and based on a clickcount for the entity. For example, table count module 202 and/or querycount module 203 can calculate occurrence rates 251, 252, 253, etc. forentities 212A, 212B, 212C, etc. respectively.

Occurrence rate calculation module 201 can send entities andcorresponding occurrence rates to feature determination module 204. Forexample, occurrence rate calculation module 201 can send entity 213A andoccurrence rate 251, entity 213B and occurrence rate 252, entity 213Cand occurrence rate 253, etc. to feature determination module 204.Feature determination module 204 can receive entities and correspondingoccurrence rates from occurrence rate calculation module 201. Forexample, feature determination module 204 can receive entity 213A andoccurrence rate 251, entity 213B and occurrence rate 252, entity 213Cand occurrence rate 253, etc. from occurrence rate calculation module201.

Method 300 includes determining a feature for use in ranking the tablerelative to other tables by aggregating the calculated occurrence ratesfor each value (303). For example, feature determination module 204 candetermine feature 261 by aggregating occurrence rates 251, 252, 253,etc. Feature 261 can indicate the popularity and/or trustworthiness oftable 211 relative to other tables. Feature 261 can be used to ranktable 211 relative to other tables, such as, for example, tables 221,and 231, or other tables in web snapshot 111 and/or curated dataset 112(e.g., in search results). Feature 261 can be sent to index buildingmodule 106 for use in formulating indices, such as, indices 121, 122,123, etc.

More popular and/or more trustworthy tables can be ranked higher insearch results.

Computing Features Of Table Attributes

FIG. 4 illustrates an example computer architecture 400 that facilitatescomputing features of table attributes. Referring to FIG. 4, computerarchitecture 400 includes semantic attribute derivation module 471,occurrence rate calculation module 401, feature determination module404, and query log 406. Each of semantic attribute derivation module471, occurrence rate calculation module 401, feature determinationmodule 404, and query log 406 can be connected to one another over (orbe part of) a network, such as, for example, a Local Area Network(“LAN”), a Wide Area Network (“WAN”), and even the Internet.Accordingly, each of semantic attribute derivation module 471,occurrence rate calculation module 401, feature determination module404, and query log 406 as well as any other connected computer systemsand their components, can create message related data and exchangemessage related data (e.g., Internet Protocol (“IP”) datagrams and otherhigher layer protocols that utilize IP datagrams, such as, TransmissionControl Protocol (“TCP”), Hypertext Transfer Protocol (“HTTP”), SimpleMail Transfer Protocol (“SMTP”), etc. or using other non-datagramprotocols) over the network.

Semantic attribute derivation module 471, occurrence rate calculationmodule 401, and feature determination module 404 can be included infeature computation module 104. Alternatively, semantic attributederivation module 471, occurrence rate calculation module 401, andfeature determination module 404 can operate outside of featurecomputation module 104.

Generally, sematic attribute derivation module 471 is configured toderive semantic attributes for cell values (i.e., intersection ofcolumn/row) in non-subject columns A semantic attribute can be derivedfrom a cell value along other related data in a table, such as, forexample, a corresponding entity value (i.e., the corresponding value inthe subject column), a column name associated with the cell, etc. Asemantic attribute can help distinguish between columns that otherwiseappear the same based on textual description. For example, two differenttables may have a column called “Population”. However, the column in onetable may refer to overall population (e.g., of a State) and the columnin the other table may refer to Asian population (e.g., of the State).Since a semantic attribute is derived from a cell value and other tabledata, semantic attributes for columns that otherwise appear the same canbe used to distinguish the columns.

Generally, occurrence rate calculation module 401 is configured todetermine the occurrence rate of semantic attributes within other tablerelated data. As depicted, occurrence rate calculation module 401further includes table count module 402 and query count module 403.Table count module 402 is configured to count how many tables (e.g.,included in web snapshot 111) include a specified semantic attribute intheir subject column.

Query log 406 contains a log of issued search queries and correspondingclick counts for Uniform Resource Locations (URLs) selected from searchresults presented in response to the issued search queries. Query countmodule 403 is configured to access a URL click count for a semanticattribute from query log 406.

In one aspect, one of table count module 402 or query count module 403is used to calculate a count representing the popularity and/ortrustworthiness of a semantic attribute. In another aspect, table countmodule 402 and query count module 403 interoperate to calculate a countrepresenting the popularity and/or trustworthiness of a semanticattribute. Popularity can indicate the frequency with which a semanticattribute is included in other tables and/or is selected from searchresults (i.e., quantity). Trustworthiness can indicate how relevant asemantic attribute is based on inclusion in other tables and/orselection from search results (i.e., quality).

Feature determination module 404 is configured to determine thepopularity and/or trustworthiness of a table by aggregating thedetermined popularity and/or trustworthiness of semantic attributes inthe table. An aggregation function can be used to aggregate semanticattribute counts into a feature of the table. The aggregation functioncan determine features using one or more of mean or median and variousquantiles.

FIG. 5 illustrates a flow chart of an example method 500 for computingfeatures of table attributes. Method 500 will be described with respectto the components and data of computer architecture 400.

Semantic attribute derivation module 471 can have access to a pluralityof tables (e.g., web tables) including tables 411 and 421. The pluralityof tables can be contained in web snapshot 111, curated dataset 112,etc. Semantic attribute derivation module 471 can access one or more ofthe plurality of tables. Semantic attribute derivation module 471 canderive semantic attributes for values in a table.

Method 500 includes accessing a table from among a plurality of tables(501). For example, semantic attribute derivation module 471 can accesstable 411. As depicted, table 411 is contained in web page 416. Web page416 is accessible via Uniform Resource Locator (URL) 417. Table 411 hassubject column 412, column 413, etc. Subject column 412 containsentities of the table including entities 412A, 412B, etc. Column 413contains corresponding attributes of the entities in (i.e., on the samerow as) subject column 412 including attributes 413A, 413B, etc. Column414 contains corresponding attributes of the entities in (i.e., on thesame row as) subject column 412 including attributes 413A, 413B, etc.Other columns of table 411 can contain other corresponding attributes ofthe entities in (i.e., on the same row as) subject column 412.

Method 500 includes for each column in the one or more other columns ofthe table and for each row of the column, deriving a sematic attributefor the row from an entity for the row, the name of the column, and thecorresponding value in the column (502). For example, semantic attributederivation module 471 can derive semantic attribute 461 for attribute413A. Semantic attribute 461 is derived from entity 412A, column (name)413, and attribute 413A. Similarly, semantic attribute derivation module471 can derive semantic attribute 462 for attribute 414A. Semanticattribute 462 is derived from entity 412A, column (name) 414, andattribute 414A. Likewise, semantic attribute derivation module 471 canderive semantic attribute 463 for attribute 413B. Semantic attribute 463is derived from entity 412B, column (name) 413, and attribute 413B.Semantic attribute derivation module 471 can also derive semanticattribute 464 for attribute 414B. Semantic attribute 464 is derived fromentity 412B, column (name) 414, and attribute 414B.

Semantic attribute derivation module 471 can send semantic attributes461, 462, 463, and 464 to occurrence rate calculation module 401.Occurrence rate calculation module can receive semantic attributes 461,462, 463, and 464 from semantic attribute derivation module 471.

In one aspect, semantic attribute derivation module 471 derives semanticattributes for any accessible tables. For example, semantic attributederivation module 471 can also derive semantic attributes for values intable 421 as well as other tables in web snapshot 111 and/or curateddataset 112. As depicted, table 421 includes subject column 422, column423, column 424, etc. Subject column 422 includes entities 422A, 422B,etc. Column 423 includes attributes 423A, 423B, etc. Column 424 includesattributes 424A, 424B, etc. Thus, semantic attribute derivation module471 can derive semantic attributes for attributes 423A, 423B, etc., andfor attributes 424A, 424B, etc.

Method 500 includes for each column in the one or more other columns ofthe table and for each row of the column, calculating an occurrence ratefor the semantic attribute by counting the occurrences of at least partof the semantic attribute within other table related data (503). Forexample, occurrence rate calculation module 401 can calculate anoccurrence rate for each of semantic attributes 461, 462, 463, 464, etc.by counting the occurrences of each of semantic attributes 461, 462,463, 464, etc. within other table related data. Calculating occurrencesin other table related data can include counting occurrences in othertables (table 421, other tables in web snapshot 111, other tables incurated data set 112, etc.) and/or accessing click count data from querylog 406 (or click logs 113).

For example, for each of semantic attributes 461, 462, 463, 464, etc.table count module 402 can calculate the number of occurrences of thesemantic attribute in other tables. Table count module 402 can calculatehow many other tables include semantic attribute 461, how many othertables include semantic attribute 462, how many other tables includesemantic attribute 463, how many other tables include semantic attribute464, etc. For example, table count module 402 can determine if semanticattribute 461 is included in table 421, etc.

Determining if a semantic attribute derived from one table is includedin another table can include comparing semantic attributes. For example,table count module 402 can compare semantic attribute 461 to semanticattributes derived from the contents of table 421. Similarly, tablecount module 402 can compare semantic attributes 461, 462, 463, 464,etc. to semantic attributers derived from tables in web snapshot 111,curated data set 112, etc.

Query count module 403 can refer to query log 406 (and/or click logs113) to access click count data for semantic attribute, such as,semantic attributes 461, 462, 463, 464, etc. derives from a tables. Forexample, query count module 403 can submit semantic query 461 to querylog 406. Query log 406 can refer to log entry 448. Log entry 448 is forquery 441. Query 441 includes a combination of entity 412A and column413. Log entry 448 indicates that URLs 442 and 417 have been selectedfrom search results presented in response to query 241. URLs 442 and417, are associated with corresponding click counts 444 and 446, and 247respectively. Each click count indicates how often a corresponding URLwas selected from presented search results.

As described, URL 417 is the URL for accessing Web page 416. As such,query log 406 can return click count 446 to query count module 403 forsemantic attribute 461. Click count 446 indicates how often URL 417 wasselected from search results presented in response to query 441 (a querythat contains both entity 412A and column (name) 413).

Query count module 403 can similarly refer to query log 206 (or clicklogs 113) for semantic attributes 462, 463, 464, etc. to obtaincorresponding click counts.

A representative query can include any query for which an ECV triplecould be an answer. Using an query for which an ECV table could be ananswer is useful with respect to surfacing answers from tables on websearch engines, given that subsets of a table can be ranked and surfaced(which may be a single row of a table or even just a single face (i.e.,a ECV triple)).

In some aspects, table count module 402 calculates an occurrence ratefor a semantic attribute based on the number of occurrences of thesemantic attribute in other tables. In another aspect, query countmodule 403 calculates an occurrence rate for a semantic attribute basedon a click count for the semantic attribute. In a further aspect, tablecount module 402 and query count module 403 interoperate to calculate anoccurrence rate for a semantic attribute based on the number ofoccurrences of the semantic in other tables and based on a click countfor the semantic attribute. For example, table count module 402 and/orquery count module 403 can calculate occurrence rates 451, 452, 453,454, etc. for semantic attributes 461, 462, 463, 464, etc. respectively.

Occurrence rate calculation module 401 can send semantic attributes andcorresponding occurrence rates to feature determination module 404. Forexample, occurrence rate calculation module 401 can send semanticattribute 461 and occurrence rate 451, semantic attribute 462 andoccurrence rate 452, semantic attribute 463 and occurrence rate 453,attribute 463 and occurrence rate 453, etc. to feature determinationmodule 404. Feature determination module 404 can receive semanticattributes and corresponding occurrence rates from occurrence ratecalculation module 401. For example, feature determination module 404can receive semantic attribute 461 and occurrence rate 451, semanticattribute 462 and occurrence rate 452, semantic attribute 463 andoccurrence rate 453, attribute 463 and occurrence rate 453, etc. fromoccurrence rate calculation module 401.

Method 500 incudes determining a feature for use in ranking the tablerelative to other tables by aggregating the calculated occurrence ratesfor each semantic attribute of the column (504). For example, featuredetermination module 404 can determine feature 467 by aggregatingoccurrence rates 451, 452, 453, 454, etc. Feature 467 can indicate thepopularity and/or trustworthiness of table 411 relative to other tables.Feature 467 can be used to rank table 411 relative to other tables, suchas, for example, tables 421, and 431, or other tables in web snapshot111 and/or curated dataset 112 (e.g., in search results). Feature 467can be sent to index building module 106 for use in formulating indices,such as, indices 121, 122, 123, etc.

In one aspect, feature determination module 404 averages a top N (e.g.,N=2, N=5, N=10) occurrence rates when determining feature 467. Averaginga top N occurrence rates can compensate for the influence of tailentities that might otherwise overly influence feature 467.

More popular and/or more trustworthy tables can be ranked higher insearch results.

Computing Features Of Table Entities

FIG. 6 illustrates an example 600 of computing static features of tableentities. As depicted, Web page 616 is accessible via URL 617. Web page616 contains table 610. Table 610 includes subject name column 611 “HTMLCommand”. In subject name column 611 are entity 611A “Head”, entity 611B“Body”, entity 611C “Style”, etc. Tables 618 (e.g., included in websnapshot 111 and/or curated data set 112) includes tables 618A and 618B.Table 618A includes subject name column 619A “Basic Commands” withentity values of head, body, etc. Table 618B includes subject namecolumn 619B “Advanced Commands” with entity values of style, etc.

Occurrence rate calculation module 601 can access table 610 and tables618. Occurrence rate calculation module 601 can determine a count forentity 611A “Head”, entity 611B “Body”, entity 611C “Style”, etc.

Table count module 602 can determine the occurrences of each of entity611A “Head”, entity 611B “Body”, entity 611C “Style”, etc. in thesubject name column of other tables. For example, table count module 602can determine that entity 611A “Head” and entity 611B “Body” occur insubject name column 619A. Similarly, table count module 602 candetermine that entity 611C “Style” occurs in subject name column 619B.

Query count module 603 can refer to query log 606 (and/or click logs113) to access click count data for each entity, such as, entity 611A“Head”, entity 611B “Body”, entity 611C “Style”, etc. For example, querycount module 603 can submit entity 611C “style” to query log 606. Querylog 606 can refer to log entry 648. Log entry 648 is for query 241, alog entry for a query that includes “style”. Log entry 248 indicatesthat URLs 642, 617, etc. have been selected from search resultspresented in response to query 241. URLs 642, 617, etc. are associatedwith corresponding click counts 644, 246, etc. respectively. Each clickcount indicates how often a corresponding URL was selected frompresented search results.

As described, URL 617 is the URL for accessing Web page 616. As such,query log 606 can return click count 646 to query count module 603 forentity 611C “style”. Click count 646 indicates how often URL 617 wasselected from search results presented in response to query 641.

Query count module 603 can similarly refer to query log 606 (or clicklogs 113) for entity 611A “Head”, entity 611B “Body”, to obtaincorresponding click counts.

In some aspects, table count module 602 calculates an occurrence ratefor an entity based on the number of occurrences of the entity in othertables. In another aspect, query count module 603 calculates anoccurrence rate for an entity based on a click count for the entity. Ina further aspect, table count module 602 and query count module 603interoperate to calculate an occurrence rate for an entity based on thenumber of occurrences of the entity in other tables and based on a clickcount for the entity. For example, table count module 602 and/or querycount module 603 can calculate occurrence rates 651, 652, 653, etc. forentities 611A “Head”, 611B “Body”, 611C “Style”, etc.

Occurrence rate calculation module 601 can send entities andcorresponding occurrence rates to feature determination module 604. Forexample, occurrence rate calculation module 601 can send entity 611A“Head” and occurrence rate 651, entity 611B “Body” and occurrence rate652, entity 611C “Style” and occurrence rate 653, etc. to featuredetermination module 604. Feature determination module 604 can receiveentities and corresponding occurrence rates from occurrence ratecalculation module 601. For example, feature determination module 604can receive entity 611A “Head” and occurrence rate 651, entity 611B“Body” and occurrence rate 652, entity 611C “Style” and occurrence rate653, etc. from occurrence rate calculation module 601.

Feature determination module 604 can determine feature 661 byaggregating occurrence rates 651, 652, 653, etc. Feature 661 canindicate the popularity and/or trustworthiness of table 611 relative toother tables. Feature 661 can be used to rank table 610 relative toother tables (e.g., in search results), such as, for example, tables618A and 619B, or other tables in web snapshot 111 and/or curateddataset 112. Feature 261 can be sent to index building module 106 foruse in formulating indices, such as, indices 121, 122, 123, etc.

Occurrence rate calculation module 601 and feature determination module604 can be included in feature computation module 104. Alternatively,occurrence rate calculation module 601 and feature determination module604 can operate outside of feature computation module 104.

Computing Features Of Table Attributes

FIGS. 7A and 7B illustrate an example 700 of computing features of tableattributes. As depicted, Web page 716 is accessible via URL 717. Webpage 716 contains table 710. Table 710 contains information for Countiesin the State of Maine. Table 710 includes subject name column 611“County name”, column “County seat”, and column “2010 population”.Tables 718 (e.g., included in web snapshot 111 and/or curated data set112) includes tables 718A and 718B. Table 718A includes subject namecolumn 719A “Counties of Maine” and column 720A “Population”. Table 718Bincludes subject name column 719B “Counties of Ohio” and column 720B“Population”.

Binary table generator 701 can access table 710. Binary table generatorcan generate (n-1) Entity-Attribute binary (“EAB”) tables for table 710,where n is the number of columns. An Entity-Attribute binary (“EAB”)table for each generated for each non-subject column of table 710. EachEAB table generated from table 710 includes subject name column 711 andone other column from table 710. For example, EAB table 710A is an EABtable for column 712. EAB table 710A includes subject name column 711and column 712. Similarly, EAB table 710B is an EAB table for column713. EAB table 710B includes subject name column 711 and column 713.

Binary table generator 701 can also generate EAB tables 719 for tables718A, 718B, etc. EAB tables 719 can be generated similar to generationof EAB tables 710A and 710B.

Binary table generator 701 can send EAB tables 710A and 710B to semanticattribute derivation module 702. Semantic attribute derivation module702 can receive EAB tables 710A and 710B from binary table generator701.

For each EAB table semantic attribute derivation module 702 can derive aset of entity-column name-value (“ECV”) triples. Each ECV tripleincludes an entity value, a column name, and an attribute value. Forexample, semantic attribute derivation module 702 can derive ECV triples720A for table 710A. Each ECV triple in ECV triples 720A, such as, forexample, EVC triples 721 and 722, include a value from subject namecolumn 711, the name of column 712, and a corresponding attribute valuefrom column 712. Similarly, semantic attribute derivation module 702 canderive ECV triples 720B for table 710B. Each ECV triple in ECV triples720B, such as, for example, EVC triples 723 and 724, include a valuefrom subject name column 711, the name of column 713, and acorresponding attribute value from column 713.

Semantic attribute derivation module 702 can send ECV triples 720A,720B, etc. to occurrence rate determination module 703.

In one aspect, binary table generator 701 sends EAB tables 719 tooccurrence rate determination module 703.

In another aspect, binary table generator 701 sends EAB tables 719 tosemantic attribute derivation module 702. Semantic attribute derivationmodule 702 can generate ECV triples from EAB tables 719. Thus, ECVtriples can be generated for columns of tables 718A, 718B, for columnsother tables in web snapshot 111, for columns of other tables in curateddata set, etc. Semantic attribute derivation module 702 then sends ECVtriples for columns of tables 718A, 718B, for columns other tables inweb snapshot 111, for columns of other tables in curated data set, etc.to occurrence rate determination module 703.

Occurrence rate determination module 703 can receive ECV triples 720A,720B, etc. from semantic attribute derivation module 702. Asappropriate, occurrence rate determination module 703 can also receiveEAB tables 710 or ECV triples corresponding to EAB tables 710.

For each of ECV triples 721, 722, etc. and ECV triples 723, 724, etc.,table count module 704 can calculate the number of occurrences of theECV triple in other tables. Determining if an ECV triple is included inanother table can include comparing the ECV triple to one or more of:the other table, EAB tables generated from the other table, or ECVtriples derived from generate EAB tables for the other table. Forexample, table count module 704 can calculate that ECV triples 723 and724 occur in table 718A.

On the other hand, an ECV triple “Franklin”-“2010 Population”-“30,768”derived from table 710 does not occur in table 718B. As depicted, table718B contains an entity “Franklin” and a column “2010 Population”.However, the value for “2010 Population” for the entity “Franklin” is1,100,000. As such, a corresponding ECV triple is“Franklin”-“Population”-“1,100,000” does match “Franklin”-“2010Population”-“30,768”. This is a correct result, since table 718B is for“Counties of Ohio”.

For each of ECV triples 721, 722, etc. and ECV triples 723, 724, etc.,query count module 706 can refer to query log 767 (and/or click logs113) to access corresponding click count data. For example, query countmodule 706 can submit ECV triple 722 to query log 767.

Various different query formats can correspond to an ECV triple. Querycount module 706 can be robust to identify queries that correspond toECV triples even when minor variations or different formats are presentbetween the content of an ECV triple and a query. Query count module 706compensate for minor variations (e.g., misspellings, less relevantnumerical differences, etc.) to appropriately identify.

For ECV triple 722, query log 767 can refer to log entry 748. Log entry748 is for query 768. It can be determined that query 768 “County Seatof Aoostock” corresponds to ECV triple 722. Query 768 is in a formatColumn Name (“County Seat”) of Entity (“Aoostock”). A different queryfor “Aoostock County Seat” can also correspond to ECV triple 722. Thequery is in a format Entity (“Aoostock”)+Column Name (“County Seat”).

Log entry 748 indicates that URLs 769 and 717 have been selected fromsearch results presented in response to query 768. URLs 769 and 717, areassociated with corresponding click counts 771 and 772 respectively.Each click count indicates how often a corresponding URL was selectedfrom presented search results.

As described, URL 717 is the URL for accessing Web page 716. As such,query log 767 can return click count 772 to query count module 706 forECV triple 722. Click count 772 indicates how often URL 717 was selectedfrom search results presented in response to query 768.

Query count module 706 can similarly refer to query log 767 (or clicklogs 113) for ECV triples 721, 723, 724 etc. to obtain correspondingclick counts.

In some aspects, table count module 704 calculates an occurrence ratefor an ECV triple based on the number of occurrences of the ECV triplein other tables. In another aspect, query count module 706 calculates anoccurrence rate for an ECV triple based on a click count for the ECVtriple. In a further aspect, table count module 704 and query countmodule 706 interoperate to calculate an occurrence rate for an ECVtriple based on the number of occurrences of the ECV triple in othertables and based on a click count for the ECV triple. For example, tablecount module 704 and/or query count module 706 can calculate occurrencerates 751, 752, 753, 754, etc. for ECV triples 721, 722, 723, and 724,etc. respectively.

Occurrence rate calculation module 703 can send ECV triples andcorresponding occurrence rates to feature determination module 707. Forexample, occurrence rate calculation module 703 can send ECV triple 721and occurrence rate 751, ECV triple 722 and occurrence rate 752, ECVtriple 723 and occurrence rate 753, ECV triple 724 and occurrence rate754, etc. to feature determination module 707. Feature determinationmodule 707 can receive ECV triples and corresponding occurrence ratesfrom occurrence rate calculation module 707. For example, featuredetermination module 707 can receive ECV triple 721 and occurrence rate751, ECV triple 722 and occurrence rate 752, ECV triple 723 andoccurrence rate 753, ECV triple 724 and occurrence rate 754, etc. fromoccurrence rate calculation module 707.

Feature determination module 707 can determine a feature for each columnof table 710. For example, feature determination module 707 candetermine feature 781 (for column 712) by aggregating occurrence rates751, 752, etc. Feature 781 can indicate the popularity and/ortrustworthiness of column 712. Similarly, feature determination module707 can determine feature 782 (for column 713) by aggregating occurrencerates 753, 754, etc. Feature 781 can indicate the popularity and/ortrustworthiness of column 712. Features 781 and 782 can be sent to indexbuilding module 106 for use in formulating indices, such as, indices121, 122, 123, etc.

Features can be used to rank columns in one table relative to othersimilar columns in other tables. One column of a table may beparticularly popular and/or trustworthy relative to other similarcolumns in other tables. As such, the column can be ranked higher thanother columns. For example, feature 782 can be used to indicate thepopularity and/or trustworthiness of column 713 relative to column 720A.

Features can also be aggregated to determine a table feature. Forexample, feature 781 and 782 can be aggregated to determine a feature oftable 710. The feature of table 710 can be used to rank table 710relative to other tables, such as, for example, tables 718, or othertables in web snapshot 111 and/or curated dataset 112 (e.g., in searchresults). The feature of table 710 can be sent to index building module106 for use in formulating indices, such as, indices 121, 122, 123, etc.

ECV triples can relate to subject-predicate-object (SPO) triples for aResource Description Framework (RDF). SPO triples can be used torepresent facts on the “semantic web”. The presences of SPO triples inan RDF knowledge base can be used to increase the ranking of a tablecontaining an ECV triple that matches an SPO triple from the knowledgebase. Similarly, ranking of a SPO in a knowledge base can be influencedby counts of the ECV fact in web tables (e.g., from a system thatreturns tuples from a knowledge base rather than one that ranks thetables).

Granularity of Feature Determination and Ranking

Features can be determined for portions of a table at any granularity,including cell and individual dimension (e.g., row or column). Rows andcolumns can be viewed interchangeably, since a table can be rotated 90degrees to transition columns to rows and transition rows to columns.Features can also be used for ranking at any granularity. If a table hasa particularly popular and/trustworthy dimension (e.g., row or column),features can be used to rank the dimension higher than other similardimensions at other tables (even if the table containing the dimensionis otherwise less popular and/or less trustworthy). Similarly, if atable has a particularly popular and/or trustworthy cell, features canbe used to rank the cell higher than other similar cells at other tables(even if the dimension and/or table containing the cell is otherwiseless popular and/or less trustworthy).

More popular and/or trustworthy cells and dimensions can be rankedhigher in search results. Search results can be presented at agranularity similar to features used to rank items returned in searchresults. For example, when a feature indicates that an individualdimension or cell of a table is more popular and/or more trustworthy,the individual dimension or cell can be presented in search results.

Other portions of a table or dimension can be omitted. For example, whena dimension is presented, other dimensions of a table can be omitted.When a cell is presented, other cells of a dimension can be omitted.Search results can include a link to omitted portions, for example, to afull dimension or full table.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed:
 1. A method for use at a computer system, the methodfor indexing a table for ranking the table, the method comprising aprocessor: accessing a table, the table including a subject column, anon-subject column, and a plurality of rows, cells of the table being atintersections between the columns and rows, the table annotated with aportion of other content relevant to describing the table; generating anindex for the table by indexing at least over data within the tablealong with the portion of other content; storing the index improving therelevance of providing the table in search results; refining the indexfor the table, comprising: deriving a semantic attribute for a cell atthe intersection of the non-subject column and a row of the table, thesemantic attribute derived by combining: (1) a value in the cell, (2)another value in another cell at the intersection of the subject columnand the row, and (3) a name value for the non-subject column into thesemantic attribute, the semantic attribute providing additionalinformation to distinguish the value in the cell from the value in othercells; calculating a frequency with which the semantic attribute isincluded in a plurality of other tables; calculating a relevance of thesemantic attribute based on inclusion of the semantic attribute in theplurality of other tables and based on features of the plurality ofother tables; determining a feature of the table by aggregating thesemantic attribute, the calculated frequency of occurrence of thesemantic attribute, the calculated relevance of the semantic attributeinto the feature of the table, and the portion of other content;refining the index for the table by indexing over the cell and thefeature of the table; and storing the refined index further improvingthe relevance of providing the table in search results; and surfacingresults from the table that satisfy a search query based on a rankingfor the table determined from the refined index.
 2. The method of claim1, wherein deriving a semantic attribute comprises combining anentity-column name-value triple for the row.
 3. The method of claim 2,wherein deriving a semantic attribute comprises: generating anentity-attribute binary table for the row, the entity-attribute binarytable having a first column corresponding to the subject column;formulating an entity-column name-value triple from the entity-attributebinary table; and wherein calculating an occurrence rate for thesemantic attribute comprises counting the occurrence rate of theentity-column name-value triple across entity-attribute binary tablesgenerated for one or more other tables.
 4. The method of claim 3,wherein the table includes a second non-subject column, and furthercomprising: deriving another semantic attribute for a further cell atthe intersection of the second non-subject column and the row, the othersemantic attribute derived by combining: (1) a further value in thefurther cell, (2) the other vales in the other cell, and (3) a namevalue for the second non-subject column into the other semanticattribute, the other semantic attribute providing additional informationto distinguish the further value in the further cell from the furthervalue in other cells; calculating another frequency with which the othersemantic attribute is included in a second plurality of other tables;calculating another relevance of the other semantic attribute based oninclusion of the other semantic attribute in the second plurality ofother tables and based on features of the second plurality of othertables; and wherein determining a feature of the table comprisesdetermining the feature of the table by aggregating the other semanticattribute, the frequency of occurrence of the other semantic attribute,and the relevance of the other semantic attribute into the feature. 5.The method of claim 4, further comprising calculating an additionalfrequency with which the other semantic attribute was selected frompresented search results; and wherein determining the feature of thetable comprises aggregating the additional frequency of the othersemantic attribute into the feature.
 6. The method of claim 1, furthercomprising: deriving another semantic attribute for a further cell atthe intersection of the non-subject column and another row, the othersemantic attribute derived by combining: (1) a further value in thefurther cell, (2) a further other value in a further other cell at theintersection of the subject column and the other row, and (3) the namevalue for the non-subject column into the other semantic attribute, theother semantic attribute providing additional information to distinguishthe further value in the further cell from the further value in othercells; calculating another frequency with which the other semanticattribute is included in a second plurality of other tables; calculatinganother relevance of the other semantic attribute based on inclusion ofthe other semantic attribute in the second plurality of other tables andbased on features of the second plurality of other tables; and whereindetermining a feature of the table comprises determining the feature ofthe table by aggregating the other semantic attribute, the frequency ofoccurrence of the other semantic attribute, and the relevance of theother semantic attribute into the feature.
 7. The method of claim 1,further comprising calculating an additional frequency with which thesemantic attribute was selected from presented search results; andwherein determining the feature of the table comprises aggregating theadditional frequency of the semantic attribute into the feature.
 8. Themethod of claim 6, wherein determining a feature of the table comprisesdetermining one or more of: a popularity of the table, or atrustworthiness of the table.
 9. The method of claim 1, whereindetermining a feature of the table comprises determining one or more of:a trustworthiness of the table or a popularity of the table.
 10. Acomputer program product for use at a computer system, the computerprogram product for implementing a method for indexing a table forranking the table, the computer program product comprising one or morehardware storage devices having stored thereon computer-executableinstructions that, when executed at a processor, cause the computersystem to perform the method, including the following: access a tablefrom system memory, the table including a subject column, a non-subjectcolumn, and a plurality of rows, cells of the table being atintersections between columns and rows, the table annotated with aportion of other content relevant to describing the table; generating anindex for the table by indexing at least over data within the tablealong with the portion of other content; storing the index improving therelevance of providing the table in search results; refining the indexfor the table, comprising: derive a semantic attribute for a cell at theintersection of the non-subject column and a row of the table, thesemantic attribute derived by combining: (1) a value in the cell, (2)another value in another cell at the intersection of the subject columnand the row, and (3) a name value for the non-subject column into thesemantic attribute, the semantic attribute providing additionalinformation to distinguish the value in the cell from the value in othercells; calculate a frequency with which the semantic attribute isincluded in a plurality of other tables; calculate a relevance of thesemantic attribute based on inclusion of the semantic attribute in theplurality of other tables and based on features of the plurality ofother tables; determine a feature of the table by aggregating thesemantic attribute, the calculated frequency of occurrence of thesemantic attribute, the calculated relevance of the semantic attributeinto the feature of the table, and the portion of other content; refinethe index for the table by indexing over the cell and the feature of thetable; and store the refined index further improving the relevance ofproviding the table in search results; and surface results from thetable that satisfy an Internet search query based on a ranking for thetable determined from the refined index.
 11. The computer programproduct of claim 10, wherein computer-executable instructions that, whenexecuted, cause the computer system to derive a semantic attributecomprise computer-executable instructions that, when executed, cause thecomputer system to combine an entity-column name-value triple for therow.
 12. The computer program product of claim 10, whereincomputer-executable instructions that, when executed, cause the computersystem to derive a semantic attribute for the row comprisecomputer-executable instructions that, when executed, cause the computersystem to: generate an entity-attribute binary table for the row, theentity-attribute binary table having a first column corresponding to thesubject column; and derive an entity-column name-value triple from theentity-attribute binary table.
 13. The computer program product of claim12, wherein computer-executable instructions that, when executed, causethe computer system to calculate an occurrence rate for the semanticattribute comprise computer-executable instructions that, when executed,cause the computer system to count the occurrence rate of theentity-column name-value triple across entity-attribute binary tablesgenerated for the plurality of tables.
 14. The computer program productof claim 12, wherein computer-executable instructions that, whenexecuted, cause the computer system to calculate an occurrence rate forthe semantic attribute comprise computer-executable instructions that,when executed, cause the computer system to: refer to a query log, thequery log containing queries and corresponding uniform resource locator(URL) click counts, for each query, the corresponding uniform resourcelocator (URL) click counts representing how often each of one of moreuniform resource locators (URLs) were selected from among search resultsresponsive to the query; and for a query representative of theentity-column name-value triple, determine a click count for a uniformresource locator (URL) to a web page containing the table.
 15. Acomputer system, the computer system comprising: one or more hardwareprocessors; and system memory coupled to the one or more hardwareprocessors, the system memory storing instructions that are executableby the one or more hardware processors, the one or more processorsexecuting the instructions stored in the system memory to: access atable from the system memory, the table including a subject column, anon-subject column, and a plurality of rows, cells of the table being atintersections between columns and rows, the table annotated with aportion of other content relevant to describing the table; generate anindex for the table by indexing at least over data within the tablealong with the portion of other content; store the index improving therelevance of providing the table in search results; refine the index forthe table, comprising: derive a semantic attribute for a cell at theintersection of the non-subject column and a row of the table, thesemantic attribute derived by combining: (1) a value in the cell, (2)another value in another cell at the intersection of the subject columnand the row, and (3) a name value for the non-subject column into thesemantic attribute, the semantic attribute providing additionalinformation to distinguish the value in the cell from the value in othercells; calculate a frequency with which the semantic attribute isincluded in a plurality of other tables; calculate a relevance of thesemantic attribute based on inclusion of the semantic attribute in theplurality of other tables and based on features of the plurality ofother tables; determine a feature of the table by aggregating thesemantic attribute, the calculated frequency of occurrence of thesemantic attribute, the calculated relevance of the semantic attributeinto the feature of the table, and the portion of other content; refinethe index for the table by indexing over the cell and the feature of thetable; and store the refined index further improving the relevance ofproviding the table in search results; and surface results from thetable that satisfy a search query based on a ranking for the tabledetermined from the refined index.
 16. The computer system of claim 15,wherein the one or more hardware processors executing the instructionsstored in the system memory to derive a semantic attribute comprises theone or more hardware processors executing the instructions stored in thesystem memory to combine an entity-column name-value triple for the row.17. The computer system of claim 15, wherein the one or more hardwareprocessors executing the instructions stored in the system memory toderive a semantic attribute comprises the one or more hardwareprocessors executing the instructions stored in the system memory to:generate an entity-attribute binary table for the row, theentity-attribute binary table having a first column corresponding to thesubject column; and derive an entity-column name-value triple from theentity-attribute binary table.
 18. The computer system of claim 17,wherein the one or more hardware processors executing the instructionsstored in the system memory to calculate an occurrence rate for thesemantic attribute comprises the one or more hardware processorsexecuting the instructions stored in the system memory to count theoccurrence rate of the entity-column name-value triple acrossentity-attribute binary tables generated for one or more other tables inthe plurality of other tables.
 19. The computer system of claim 17,wherein the one or more hardware processors executing the instructionsstored in the system memory to calculate an occurrence rate for thesemantic attribute comprises the one or more hardware processorsexecuting the instructions stored in the system memory to: refer to aquery log, the query log containing queries and corresponding uniformresource locator (URL) click counts, for each query, the correspondinguniform resource locator (URL) click counts representing how often eachof one of more uniform resource locators (URLs) were selected from amongsearch results responsive to the query; and for a query representativeof the entity-column name-value triple, determine a click count for auniform resource locator (URL) to a web page containing the table. 20.The computer system of claim 15, wherein the one or more hardwareprocessors executing the instructions stored in the system memory todetermine a feature of the table comprises the one or more hardwareprocessors executing the instructions stored in the system memory todetermine one or more of a popularity and a trustworthiness of thetable.